1. Field of the Invention
This invention relates to scissors with replaceable cutting blades particularly suited to individuals such as barbers who make frequent use of scissors.
2. Description of the Prior Art
As shown in FIGS. 6, 7 and 8, conventional scissors with replaceable cutting blades include a movable blade 3 and a fixed blade 4, each of which comprises a cutting edge 1 and a handle 2. The movable blade 3 and the fixed blade 4 are pivotally joined by a screw 5. When it is desired to increase the resistance of the moving blade 3 to the fixed blade 4 so that such resistance will conform to the hardness of hair or to the gripping force of the individual barber, the tightness of the screw 5 is suitably adjusted.
The cutting edge 1 of scissors of this type has a shank 6 at its base end, and the handle 2 has a groove 7 which receives the shank 6. The shank 6 has a pair of threaded screw holes 8a, 8b, and an unthreaded screw hole 9 located between the two holes 8a, 8b. The groove 7 has through-holes 10a, 10b and 11 which register respectively with the screw holes 8a, 8b and 9 when the shank 6 is fitted into the groove 7. The holes 10a, 10b, 11 are sized to agree with the holes 8a, 8b, 9, respectively. Accordingly, by screwing screws 12a, 12b into the threaded screw holes 8a, 8b via the through-holes 10a, 10b from the side opposite the groove 7 of handle 2, the cutting edge 1 and the handle 2 are fixed together and the movable blade 3 and fixed blade 4 are formed. As shown in FIG. 6, the two blades 3 and 4 are joined by passing the screw 5 through the aligned through-holes 9, 11 and tightening the screw by a nut.
When the cutting blade 1 needs to be replaced owing to dulling or nicking of the edge with long use, the screw 5 is withdrawn, the movable blade 3 and fixed blade 4 are separated from each other and then the screws 12a, 12b are withdrawn to separate the cutting blade 1 from the handle 2. A new cutting blade 1 is attached to the handle 2 and the movable and fixed blades 3, 4 are rejoined by the screw 5 by reversing the above-described procedure.
Barbers find such replacement solely of the cutting blade 1 highly useful since professional people who can grind and sharpen are presently in short supply.
As will be understood from FIGS. 6, 7 and 8, the example of the prior art is such that the small screws 12a, 12b are screwed into the screw holes 8a, 8b to secure the cutting blade 1 to the handle 2. However, in scissors of this type, the movable blade 3 is moving repeatedly a more large number of times relative to the fixed blade 4, and the resistance met by the cutting blade constantly changes. Owing to these harsh operating conditions, the screws 12a, 12b loosen and the cutting blade 1 develops play. Consequently, it is necessary to retighten the screws 12a, 12b with a screwdriver. However, since the screw holes 8a, 8b are short in length and the screw threads are small, repeated retightening of the screws 12a, 12b causes the screw holes 8a, 8b to be enlarged, thereby necessitating that the cutting blade 1 be replaced regardless of the fact that the cutting blade may still be sharp. This is not economical.
Other drawbacks are that replacement cannot be performed in a simple manner, and that a user who is not a scissors specialist cannot perform the replacement simply or accurately.